Sheet folding machine



June 30, 1970 M. E. FLYGARE 3,517,919

SHEET FOLDING MACHINE Filed Sept. 11. 1967 2 Sheets-Sheet 1 .INVENTOR.

SHEET FOLDING MACHINE Filed Sept. 11. 1967 2 Sheets-Sheet I: 21 I i Q W gal-m H 15 m 3% r I:

56-35%! Hhhh. 1 L I l 1.

, a INVENTOR.

B m/ 5 FIN/634.65 FIESC' jwfW 47'7292/VEV United States Patent SHEET FOLDING MACHINE Melvin E. Flygare, Kenmare, N. Dak., assignor to Maintenance-Free Machines, Inc., Kenmare,

N. Dak., a corporation of North Dakota Filed Sept. 11, 1967, Ser. No. 666,616 Int. Cl. B65h 45/14 US. Cl. 270-68 4 Claims ABSTRACT OF THE DISCLOSURE The invention relates to a machine for automatically folding textile sheet material both transversely and longitudinally. Means is provided for conveying the sheet and lifting the leading edge thereof to thereby form a bight as the trailing portion of the sheet passes beneath the leading edge. The leading edge is subsequently released in registration with the trailing edge of the sheet to thereby fold the sheet transversely to its direction of travel. The invention includes a cantilevered elongate member extending beyond the discharge end of the conveyor for receiving and supporting the transversely folded sheet material in draped fashion to thereby form a longitudinal fold in the sheet. Means is also provided for adjusting the speed of operation of the means for lifting and holding the leading edge of the sheet to thereby insure asecure hold on the leading edge of the sheet and to also insure that the leading edge is released in registration with the trailing edge to thereby produce a neatly folded sheet.

BACKGROUND OF THE INVENTION The invention pertains to the field of machines 'for automatically folding sheet material both transversely and longitudinally. More particularly, it pertains to means for adjusting the speed of operation of the transverse sheet folding mechanism and means for producing a longitudinal fold in the sheet upon discharge from the transverse sheet folding mechanism.

A number of machines for automatically making transverse folds in textile sheet material exist in the prior art. Examples of such machines include those disclosed in the following US. patents: Cran et al. 2,811,350; Cran 2,815,946; Gram 2,949,294; Bergman et al. 3,005,630; Jensen 3,079,143; Jensen 3,116,059; and Cran 3,276,768. While each of the above patents discloses means for automatically transversely folding sheet material including a mechanism for lifting the leading edge of the sheet material as the trailing portion forms a bight and passes thereunder as well as means for subsequently releasing the leading edge, none of the patents disclose any means for conveniently adjusting the speed of operation of the means for lifting and subsequently releasing the leading edge of the sheet material. Moreover, the prior art devices such as the machine disclosed in Kamberg Pat. 3,260,518 which provide means for making a longitudinal fold in the sheet material, rely on mechanisms such as pinch rollers and others all far more complicated than the simple and maintenance free means for making a longitudinal fold of the present invention.

The present invention, through the provision of pneumatically operated lifting and holding elements, provides for a convenient adjustment of the speed of operation thereof. Consequently, the grip of the mechanism on the leading edge of the textile sheet material can be adjusted and, more importantly, the timing of the release of the leading edge can be sensitively adjusted so that it is released in precise registration with the trailing edge of the sheet material as it passes beneath the leading edge to thereby form a neatly folded sheet. A simple, main- 3,517,919 Patented June 30, 1970 "ice tenance free and convenient means for forming a longitudinal fold in the sheet material upon its discharge from the conveyor is provided and consists of a cantilevered elongate member disposed to support the transversely folded sheet material in draped fashion upon discharge from the conveyor.

SUMMARY The invention concerns apparatus for transversely and longitudinally folding sheet material and comprises a frame, conveyor means mounted to the frame for conveying the sheet material in a flat position and in a substantially horizontal plane to thereby define a direction of travel, means for folding the sheet material during its travel in a direction transverse to the direction of travel, and a generally horizontal elongate supporting surface mounted to the frame at the discharge end of the conveyor extending in the direction of travel of the sheet material substantially in the plane thereof to thereby receive and support the sheet material in draped fashion upon its discharge from the conveyor means to form a longitudinal fold in the sheet material.

The mechanism for forming the transverse folds in the sheet material as it is conveyed includes sheet lifting means mounted for pivotal movement about an axis below the plane of the conveyor means transverse to the direction of travel of said sheet material and extending substantially the Width of the sheet material, sheet holding means mounted for pivotal movement about an axis above the plane of the conveyor means transversely to the direction of travel downstream from the sheet lifting means and extending substantially the width of the sheet material in proximity to the sheet lifting means, a fixed surface above the plane of the conveyor means extending substantially the width of the sheet material and engageable by the sheet holding means when the sheet holding means is pivoted upwardly to thereby pinch the leading edge of the sheet material and hold the leading edge in a fixed position above the conveyor means, mechanical means linking the sheet lifting means and the sheet holding means for coordinating the movement thereof, and pneumatic means for pivoting the sheet holding means into and out of engagement with the fixed surface in response to the passage of the leading and trailing edges, respectively, of the sheet material.

The actuation of the sheet lifting means is controlled by a pair of series connected switches disposed upstream from the sheet holding means. The switches are actuated by the passage of the sheet material and control the pickup of the leading edge of the sheet as well as the release thereof in registration with the trailing edge of the sheet material as it passes beneath the leading edge. Means is provided for adjusting the input pressure to and exhaust rate from the pneumatic means for pivoting the sheet holding means to thereby adjust the speed of operation thereof. Adjustment of the speed of operation provides sensitive control the gripping and release of the leading edge of the sheet material in precise registration with the the trailing edge of the material. The generally horizontal elongate supporting surface provided to form a longitudinal fold in the sheet material comprises an elongate member cantilevered from and beyond the frame of the machine at the discharge end of the conveyor in the direction of travel of the conveyor to thereby receive, in draped fashion, the transversely folded sheet material as it is discharged from the conveyor means.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view and a partial sectional view of the present invention. In FIG. 1 certain elements are shown schematically;

FIG. 2 is a top View of the sheet folding machine which comprises the present invention;

FIGS. 3A, 3B, and 3C are vertical sectional views taken on the line 33 of FIG. 2 and show the sheet lifting and holding means in various stages of operation. FIG. 3A shows the pneumatically actuated means for operating the sheet lifting and sheet holding means as well as the switching means for controlling the operation of the sheet lifting and holding means in response to the passage of the sheet material, and

FIG. 4 is a vertical sectional view taken on the line 4-4 of FIG. 2 and shows the mechanical linkage between the sheet lifting and sheet holding means.

DESCRIPTION OF THE PREFERRED EMBODIMENT The general principles of the present invention may be understood with reference primarily to FIGS. 1 and 2. Sheet material, S, is pressed in mangle, M, and discharged onto the sheet folding machine which comprises the present invention. Sheet folding machine 10 automatically folds sheet material, S, twice in a direction transverse to its direction of travel and once in a direction coincident with the direction of travel, in a manner described in detail below.

In general sheet folding machine 10 includes a frame 11 mounted to legs 12. A series of spaced conveyor belts 13 extend from one end of frame 11 to the other and are mounted on rollers 14 which are rotatable in bearings 15 mounted to frame 11. Belts 13 are driven in a manner described below to convey sheet material, S, in a direction from left to right as viewed in FIG. 1.

The means for driving conveyor belts 13 is shown in FIGS. 1 and 2 and includes a motor 20, transmission 21 and a belt 22. Belt 22 extends from the output pulley 23 of transmission 21 to roller pulley 24 keyed to roller 14. Thus motor drives conveyor belts 13 in a clockwise direction as viewed in FIG. 1 to thereby provide the means for conveying sheet material, S, at a speed in the range of 80 to 130 feet per second depending upon the discharge rate of mangle, M. In the preferred embodiment of the invention belts 13 are driven at the rate of approximately 90 feet per second.

A pair of identical bridge assemblies extend across conveyor belts 13 from one side of frame 11 to the other. Bridge assemblies 30 serve to grip and elevate the leading edge of sheet material, S, to thereby allow the trailing portion to form a bight and pass thereunder as it continues to be conveyed on belts 13. Sheet material, S, is consequently folded in a direction transverse to its direction of travel in two distinct manipulations by each of the two bridge assemblies 30 to produce a four-ply folded sheet.

Bridge assemblies 30 include sheet lifting means 31 mounted beneath the upper plane of travel of conveyor belts 13 for pivotal movement about the axis of shaft 32. Sheet lifting means 31 includes a series of spaced lifting fingers 33 which are pivotable upwardly into the space between adjacent conveyor belts 13. Bridge assembly 30 also includes sheet holding means 35 which includes a sheet gripping blade 36 mounted for pivotable movement to shaft 37 about the longitudinal axis thereof. Sheet holding means 35 operates in conjunction with sheet lifting means 31 and bridge 39, in a manner described more particularly below, to grip the leading edge of the sheet material, 8, as it passes thereunder on conveyor belts 13. Switching means 40 is also a part of bridge assembly 30 and serves to coordinate the action of sheet lifting means 31 and sheet holding means 35 in response to the passage of sheet material, S, in a manner described more particularly below.

Sheet folding machine 10 includes a generally elongate supporting surface provided by rod which is mounted to frame 11 at the discharge end of conveyor belts 13 and extends beyond frame 11 in the plane of conveyor 4 belts 13 and in the direction of travel thereof. Rod 50 serves to receive the transversely folded sheet material, S, upon its discharge from conveyor belts 13, in draped fashion, best seen in FIG. 1, to thereby cause sheet material, S, to be folded longitudinally.

The general operation of the present invention may be readily understood with reference to FIGS. 1 and 2. Mangle, M, discharges sheet material, S, in a fiat position onto conveyor belts 13 Which convey the material toward bridge assemblies 30. After the leading edge of sheet material, S, passes beneath switching means 40, gripping blade 36 is actuated to raise the leading edge above the plane of conveyor belts 13 to allow the trailing portion of sheet material, S, to form a bight and pass thereunder. When the trailing edge passes switching means 40 the leading edge of the sheet material, S, is released and the once transversely folded material is conveyed to the downstream bridge assembly for the second transverse fold, which is made in an identical manner. When the sheet completes its passage through the downstream bridge assembly and is in a twice transversely folded condition, conveyor belts 13 discharge the sheet material onto rod 50 as shown in FIG. 1. Rod 50 causes a longitudinal fold to be made in the sheet material. The machine attendant then removes sheet material, S, from rod 50 and, in so dong, makes the final longitudinal fold.

With the foregoing general description of the apparatus and its operation, the following detailed description may be readily understood. With reference primarily to FIG. 3A, sheet lifting means 31 includes a series of spaced lifting fingers 33 rigidly mounted to bar which is mounted to shaft 32. Shaft 32 is journaled on opposite sides of frame 11 below the plane defined by the upper run of conveyor belts 13. Lifting fingers 33 extend from bar 55 in a downstream direction, that is, in the direction of movement of the upper run of conveyor belts 13. Lifting fingers 33 are pivotable about the axis of shaft 32 from a substantially horizontal plane (see FIG. 3B) to an inclined plane extending from a point below the plane of the upper run of conveyor belts 13 to a point above the plane and downsteram from the axis of shaft 32. Thus, when pivoted into the inclined plane, lifting fingers 33 serve as a ramp for lifting sheet material, S, as the leading edge engages lifting fingers 33 and conveyor belts 13 continue to convey the material.

Sheet holding means 35 includes a grippng blade 36 mounted to bar 56 which is axially secured to shaft 37 journaled on opposite sides of frame 11. Gripping blade 36 operates in association with fixed surface 58 of bridge 39 which extends across the entire width of the sheet folding machine in a substantially horizontal plane above conveyor belts 13. Fixed surface 58 is formed with a resilient strip of material 59 secured to bridge 39.

A similar layer of resilient material may be secured to the edge of gripping blade 36 as shown at 60. Gripping blade 36 is pivotable about the shaft 37 in a generally upward direction opposing the direction of travel of the upper run of conveyor belts 13, into engagement with fixed surface 58 of bridge 39 to serve as a means for pinching and holding the leading edge of sheet material, S, in a fixed position above the plane of conveyor belts 13. For that purpose lifting blade 36 is disposed in close proximity to lifting fingers 33 when the latter assume their inclined position, as shown in FIG. 3A, to thereby receive the leading edge of sheet material, S, as it passes over and beyond lifting fingers 33.

The action of sheet lifting means '31 and sheet holding means 35 is coordinated through the mechanical linkage shown in FIG. 4. When gripping blade 36 moves into contact with fixed surface 58 to thereby grip the leading edge of the sheet material, S, as shown in FIG. 3B, the linkage insures that lifting fingers 33 of sheet lifting means 31 move into a substantially horizontal plane beneath the upper run of conveyor belts 13. When gripping fingers 33 are in an inclined plane to thereby serve as a ramp for sheet material, S, being conveyed on conveyor belts 13, the linkage insures that gripping blade 36 is in its downward pivoted position in close proximity to the ends of gripping fingers 37, as sown in FIG. 3A. The linkage includes a bracket 60 fixed to shaft '37 and consequently arcuately movable by shaft 37 when shaft 37 is pivoted. A link 61 is pivotally connected to bracket 60 at one end and is similarly pivotally connected to arm 62 at the other end. Arm 62 is fixed to shaft 32 of sheet lifting means 31. Thus as gripping blade shaft 37 is pivoted, by actuating means described below, bracket 60, link61 and arm 62 cause shaft 32 to be pivoted about its axis and lifting fingers 33 of sheet lifting means 31 pivot upwardly or downwardly, as the case may be.

The means for actuating sheet gripping means 35 and sheet lifting means 31 may be best understood with reference to FIG. 3A. Bracket 70 is fixed to shaft 37. A pneumatic cylinder and piston 71 having a connecting rod 72 pinned to bracket 70 is mounted to frame 11. Cylinder and piston 71 is operated, to thereby pivot bracket 70 about the axis of shaft 37 and pivot gripping blade 36 upwardly into engagement with fixed surface 58, by means of input pressure from air supply 75. The input pressure from air supply 75 is controlled by a shutoff valve 76, a needle valve 77, a solenoid operated valve 78 and an exhaust control valve 79. Solenoid controlled valve 78 is operated by solenoid 80.

Pneumatic piston and cylinder 71 is of the type supplied by Unipress Company, Minneapolis, Minn., and exemplified by Unipress Item No. LM-240A. Shutoff valve 76 is simply a hand operated valve which may be chosen from any number of valves available by those skilled in the art. Needle valve 77 is of the type available from the Unipress Company, Minneapolis, Minn., designated, Regulating Valve, Item No. G-149A. Solenoid control valve 78 in combination with solenoid 80 is of the type supplied by the Unipress Company and designated, Skinner Electric Valve, Item No. V5L-3418OST, 115 volts, 60 cycle, watt, Serial No. VE6. Exhaust valve 79 is of the type supplied by T.E.C. Specialty Company, Atlanta, Ga., and designated pneumatic bypass valve, Item No. PR-6100.

Needle valve 77 constitutes means for adjusting the input pressure from air supply 75 to thereby adjust the speed of operation of piston and cylinder 71 and, consequently, the speed of operation of sheet lifting means 31 and sheet holding means 35. Exhaust valve 79, of the pneumatic bypass type, represents means for adjusting the rate of exhaust from piston and cylinder 71 to thereby adjust the speed of operation of sheet lifting means 31 and sheet holding means 35. The exhaust valve 79 serves to adjust the rate at which the leading edge of sheet material, S, is released and, consequently, serves as a means for insuring that the leading edge is released in precise registration with the trailing edge of sheet material, S, to thereby form a neat fold.

The means for actuating sheet lifting means 31 and sheet holding means 35, described immediately above, is controlled through the energizing and de-energizing of solenoid 80 by means of switch means 40. With reference primarily to FIG. 3A, switch means 40, mounted on the upstream side of bridge 39, includes an elongate U- shaped bracket 41 extending upstream in spaced parallel relationship with conveyor belts 13. Two switches 42 and 43 are mounted to bracket 41. The switches are series connected with power supply 44 and solenoid 80 through conductors 45 and 46. Switch 42 is provided with a sensor 47 which, when suspended freely, extends downwardly into the space between the central conveyor belts 13, as best seen in FIG. 3C. Switch 42 is normally open and is closed when the leading edge of sheet material, S, contacts sensor 47 and causes it to swing arcuately in the direction of travel of conveyor belts 13, to thereby close switch 42. Switch 42 is held in its closed position until the trailing edge of sheet material, S, passes sensor 47 and it is then free to swing downwardly to assume the position shown in FIG. 3C and open switch 42. Switch 43 is provided with sensor 48 which, when suspended freely, also extends into the space between the central conveyor belts 13. Like sensor 47, sensor 48 is contracted by the leading edge of sheet material, S, and is caused to swing arcuately to thereby close normally open switch 43. Switch 43 remains in a closed position until the leading edge of sheet material, S, is released from engagement with lifting blade 36 of gripping means 35, and fixed surface 58.

Switches 42 and 43 are available with nylon sensors from the Kohnstamm Company, Omaha, Nebr., under the trademark Microswitch.

The closing of switch 43, when switch 42 is in a closed condition, controls the movement of sheet gripping means 35 into engagement with fixed surface 58, to thereby grip the leading edge of the sheet, while sheet lifting means 31 simultaneously moves into a horizontal plane, as shown in FIGS. 3A and 3B. Switch 42, when opened, controls the release of the leading edge of sheet material, S, and the simultaneous movement of sheet lifting means 31 upwardly about its horizontal axis, as shown in FIG. 30.

Means for discharging air into the bight of sheet material, S, generally beneath fixed surface 58, substantially throughout the entire width of sheet material, S, is provided by tubing 81 shown in FIGS. 3A, 3B and 3C. Tubing 81 is provided with a series of inch holes on 6 inch centers directed toward the bight of sheet material, S. When the leading edge of sheet material, S, is gripped by gripping means 35 and fixed surface 58, as shown in FIG. 3B, a stream of air is discharged from tubing 81 to thereby cause a slight billowing of the bight portion of sheet material, S. The slight billowing prevents humping of the trailing portion of sheet material, S, and insures that the trailing portion of sheet material, S, moves with fluidity on conveyor belts 1'3.

It should be noted that a gap shown at in FIGS. 3A, 3B and 3C is provided in fixed surface 58 of bridge 39 to accommodate sensor 48 of switch 43 when sensor 48 is pivoted by the leading edge of sheet material S, to close switch 43. A similar gap is provided in lifting blade 36 and shown at 91 n FIGS. 3A, 3B and SC to serve a similar purpose. Thus when sensor 48 is in its extreme displaced position, shown in FIG. 3B, gap 90 in fixed surface 58 as well as gap 91 in lifting blade 36 accommodate sensor 48.

The means for making the longitudinal fold in sheet material, S, may be seen in FIGS. 1 and 2 and consists of rod 50 which is cantilevered from frame 11 in the plane of the upper run of conveyor belts 13 and extends beyond the discharge end thereof. Rod 50 is mounted to frame 11 by means of cover plate 95 which is held in secured relationship with frame 11 by means of screws 96. Rod 50 extends from cover plate 95 arcuately and initially rearwardly through the space in the center of conveyor belts 13 and then in a forward direction in the plane of conveyor belts 13 to thereby insure a smooth and uninterrupted acceptance of sheet material, S, as it is discharged from conveyor belts 13. Upon discharge, sheet material, S, is draped over rod 50, as best seen in FIG. 1, and a longitudinal fold is thereby made.

With the foregoing general and detailed description of the apparatus and general description of its operation, the following detailed description of the operation of the invention may be readily understood. With reference to FIG. 1, sheet material, S, is discharged frommangle, M, onto conveyor belts 13. The sheet lifting means 31 and sheet holding means 35 in both bridge assemblies 30' are in the position shown in FIG. 3A. As the leading edge of sheet material, S, contacts sensor 47 of switch 42, the switch is closed. Switch 43 remains open and consequently solenoid 80 is not energized. As the leading edge of sheet material, S, contacts lifting fingers 33 of sheet lifting means 31 the sheet is caused to ride upwardly and the leading edge contacts sensor 48 as shown in FIG. 3A. As sheet material, S, continues to be conveyed by conveyor belts 13, sensor 48 is further displaced and switch 43 closes. With both switches 42 and 4-3 closed solenoid 80 is energized and opens valve 78. Air pressure from compressed air supply 75 then passes from valve 78 through valve 79 and actuates piston and cylinder 71. Connecting rod 72 of piston and cylinder 71 is driven to the left, as viewed in FIG. 3A, and bracket 70 is pivoted about the axis of shaft 37 to pivot gripping blade .36 of sheet holding means 35 upwardly into engagement with fixed surface 58. The leading edge of sheet material, S, is therefore held in a fixed position above conveyor belts 13. Simultaneously, due to the linkage shown in FIG. 4, sheet lifting fingers 33 of sheet lifting means 31 is pivoted downwardly out of the plane of the upper run of conveyor belts 13 to thereby allow the sheet material, S, to form a bight and pass under gripping blade 36 of sheet holding means 35, as shown in FIG. 3B. Air is then introduced into tubing 81 to discharge into the bight of sheet material, S, and cause the slight billowing effect explained above, and as shown in FIG. 3B.

As the trailing edge of sheet material, S, passes sensor 47 of switch 42, sensor 47 is free to swing downwardly into the position shown in FIG. 3C and switch 42 opens. Solenoid "80 is therefore de-energized and valve 78 closes. The closing of valve 78 deprives exhaust valve 79 of air pressure from air supply 75 and, due to the design of exhaust valve 79, the pressure formerly acting in piston and cylinder 71 is exhausted. The weight of lifting blade 36 is then free to pivot downwardly about the axis of shaft 37 out of engagement with fixed surface 58, as connecting rod 72 and the piston of piston and cylinder 71 move to the right as viewed in FIG. 3A. The leading edge of the sheet is consequently released from its fixed position, in registration with the trailing edge of sheet material, S, and the folded sheet exits from bridge assembly 30 as shown in FIG. 3C.

The once transversely folded sheet then passes through the downstream bridge assembly 30 and an identical operation occurs to produce a second transverse fold in sheet material, S.

Needle valve 77 may be adjusted to thereby control the supply of air presure to valve 78 and to consequently control the speed of operation of piston and air cylinder 71 which, in turn, controls the speed of the pivotal movement of lifting blade 36. Thus an adjustment can be made to insure that a secure grip is obtained on the leading edge of sheet material, S.

Exhaust valve 79 can also be adjusted to control the rate of exhaust of piston and cylinder 71 to thereby control the rate of release of the leading edge of sheet material, S. Thus an adjustment can be made to insure that the leading edge of sheet material, S, is released in precise registration of the trailing edge so that a neatly folded product results.

The twice transversely folded sheet material is then conveyed by conveyor belts 13 to discharge onto rod 50 shown in FIGS. 1 and 2. As explained above, sheet material, S, discharges from conveyor belts 13 and drapes over rod 50 which produces a longitudinal fold. The machine attendant then removes the twice transversely folded and once longitudinally folded sheet material from rod 50 and, in so doing, makes the final transverse fold, to complete the folding operation.

It should be recognized that changes may be made in the form of the invention to depart from the embodiment shown, without departing from the scope of the appended claims. For example, the plane of the upper run of conveyor belts 13 may be inclined so that the sheet material is conveyed up or down hill since the conveyance of the sheet material in a horizontal plane is not critical. In

addition rod 50 may be replaced by numerous other structures which provide an elongate supporting surface to receive sheet material, S, in draped fashion, upon its discharge from conveyor belts 13. For example, a vertical rigid sheet may be provided with its upper edge positioned to receive and support sheet material, S, upon its discharge from conveyor belts 13. Other changes may be made in the embodiment shown and described by those skilled in the art without departing from the scope of the following claims.

What I claim is:

1. Apparatus for transversely and longitudinally folding sheet material comprising:

a frame;

conveyor means mounted to said frame for conveying said sheet material in a flat position to thereby define a direction of travel;

sheet lifting means mounted for pivotal movement about an axis below the plane of said conveyor means transverse to said direction of travel and extending substantially the Width of said sheet material;

sheet holding means mounted for pivotal movement about an axis above the plane of said conveyor means transverse to said direction of travel and extending toward said sheet lifting means downstream therefrom substantially the width of said sheet material in proximity to said sheet lifting means;

a fixed surface above the plane of said conveyor means,

extending substantially the width of said sheet material, and engagable by said holding means when said sheet holding means is pivoted upwardly in a direction opposing said direction of travel of said sheet material;

mechanical means linking said sheet lifting means and said sheet holding means for coordinating the pivotal movement thereof, said sheet lifting means being disposed in a substantially horizontal plane below said conveyor means when said sheet holding means is pivoted upwardly into engagement with said fixed surface, and said sheet lifting means being disposed in an inclined plane intersecting said plane of said conveyor means when said sheet holding means is pivoted out of engagement with said fixed surface;

pneumatic means for pivoting said sheet holding means into engagement with said fixed surface in response to the passage of said leading edge and for releasing said leading edge of said sheet material in registratration with said trailing edge as said trailing edge passes thereunder, said pneumatic means comprising a pair of series connected switches disposed upstream from said fixed surface, one switch being disposed upstream from the other; means responsive to the passage of said leading and trailing edges of said sheet material for actuating said switches; an air supply; a pneumatically actuated cylinder and piston linked to said sheet holding means; valve means responsive to the actuation of both of said switches by said sheet material for connecting said air supply with said pneumatically actuated cylinder and piston for actuating said piston to thereby pivot said sheet holding means into engagement with said fixed surface; and means for exhausting said cylinder in response to deactuation of one of said switches; and;

a generally horizontal elongate supporting surface mounted to said frame at the discharge end of said conveyor means and extending in said direction of travel of said sheet material substantially in the plane thereof, to thereby receive and support said sheet material in draped fashion upon discharge from said conveyor means.

2. The apparatus of claim 1 and means for adjusting the input pressure from said air supply to thereby adjust the speed of operation of said sheet holding and said sheet lifting means.

3. The apparatus of claim 2 and means for adjusting the rate of exhaust of said cylinder to thereby adjust the 3,094,321 6/1963 Kamberg 27068 speed of operation of said sheet holding and said sheet 3,116,059 12/ 1963 Jensen 27068 lifting means. 3,260,518 6/ 1966 Kamberg et a1 27068 4. The apparatus of claim 3 and means for discharging 3,361,424 2/ 1968 Kamberg 27068 air into the bight of said sheet material beneath said fixed surface substantially throughout the width of said sheet 5 FOREIGN TE material to thereby prevent humping. 521,310 5/ 1940 Great Bfltlall- 852,898 11/1939 France. References Cited UNITED STATES PATENTS 10 LAWRENCE CHARLES, Primary Examiner 2,949,294 8/1960 Cran 27068 

